This invention relates generally to paintball guns. More specifically, this invention relates to a paintball gun on/off valve for selectively controlling a supply of gas from a compressed gas source.
The industry has been unable to provide a reliable on/off valve for selectively supplying a flow of compressed CO.sub.2 gas to a paintball gun from a CO.sub.2 gas source. In particular, on/off valves of the prior art have problems, such as leakage of the CO.sub.2, and are therefore unreliable.
FIG. 1 is a perspective view of a paintball gun 50 having an on/off valve 100 according to the prior art. FIG. 2 is an enlarged side elevation view of the on/off valve 100 of FIG. 1, showing the external attachment between a pressure regulator 55 of a paintball gun 50 and a compressed gas source 60. The on/off valve 100 of FIGS. 1 and 2 is typical for guns using compressed air or nitrogen as the compressed gas source 60. FIG. 2A is a side elevation view of an on/off valve 100A, similar to the valve 100 shown in FIGS. 1 and 2. The compressed gas source 60A, used with the valve 100A, is CO.sub.2. FIG. 3 is a bottom right side perspective view of the prior art on/off valve 100A of FIG. 2A, shown independent of attachment to external components. The only structural differences between the valve 100 shown in FIGS. 1 and 2 and the valve 100A of FIGS. 2A and 3 are the type of actuator 122 used and the size of the valve. FIGS. 1 and 2 show a lever-type actuator 122 on a larger valve for use with a compressed air or nitrogen gas source 60, while FIG. 3 shows a knob-type actuator 122A for use with a compressed CO.sub.2 gas source 60A.
The internal configuration of the conventional on/off valves 100, 100A is shown in FIGS. 4-7. Specifically, FIG. 4 is a horizontally cross-sectioned bottom plan view of the prior art on/off valve 100A, shown in FIG. 3. FIG. 5 is an enlarged, vertically cross-sectioned, partial right side elevation view of the prior art on/off valve 100A of FIG. 3. FIG. 6 is a front elevation view and a cutaway left side elevation view of a plug 120 for use in the prior art on/off valve 100A of FIG. 3. FIG. 7 is a horizontally cross-sectioned bottom plan view and a vertically cross-sectioned front elevation view of a valve body 102 for use in the prior art on/off valve 100A of FIG. 3. The general internal configuration of the valve 100 is the same as that for valve 100A, except with respect to the sizing of the components.
Referring to FIGS. 4-7, the prior art on/off valve 100A has a valve body 102 with a gas inlet 110 and a gas outlet 112 extending longitudinally through the body 102. The valve body 102 also includes a plug cavity 115 that extends laterally through the body 102 between the inlet 110 and the outlet 112 from a right side (top of FIG. 4) to a left side (bottom of FIG. 4) of the body 102. A plug 120 is positioned within the plug cavity 115. The plug includes a knob (or other actuator) 122A that can be rotated 90.degree. to switch the valve 100A on or off. The actuator 122A is attached to a plug stem 124 that extends into and through the plug cavity 115. A flow aperture 125 is provided through the plug stem 124, and is located at the lateral position of the inlet 110 and the outlet 112, when the plug stem 124 is properly arranged inside the cavity 115.
Two o-rings 126, 126A extend around the plug stem 124 within grooves 127, 127A on opposite lateral sides of the inlet 110 and outlet 112. These o-rings 126, 126A provide a seal between the plug stem 124 and the wall of the cavity 115 to prevent the gas from leaking out through the plug ends and to ensure that the gas from the gas inlet 110 travels to the gas outlet 112 when the valve 100A is open. A third o-ring 128 is provided along the external surface of the plug stem 124 within a circular-shaped groove 129. The third o-ring 128 is designed to prevent gas from leaking into the outlet 112 and, hence, from flowing to the gun 50, when the actuator 122A is in an "off" (closed valve) position. Specifically, when the actuator 122A is located in an "off" position, the o-ring 128 surrounds an entry port 113 of the outlet 112, preventing the gas from entering the outlet 112. It should be noted that the third o-ring 128 only performs its sealing function when the valve is in the "off" position.
Referring to FIGS. 1-7, the operation of the prior art on/off valves 100, 100A is as follows. When the actuator 122, 122A is located in an "on" (open valve) position, the flow aperture 125 in the plug stem 124 is arranged in communication with both the inlet 110 and the outlet 112 in order to permit the gas to flow from the inlet 110 to the outlet 112. When the actuator 122, 122A is rotated 90.degree. from the open position into a closed position, the third o-ring 128 slides into place around the entry port 113 of the outlet 112, and the flow aperture 125 is positioned transverse to an axis running from the inlet 110 to the outlet 112. This prior art system works fairly well for compressed air and Nitrogen systems which have larger valve sizes.
Unfortunately, however, this configuration has several disadvantages when used for CO.sub.2 systems, which generally have smaller valves. In particular, the wall of the plug cavity 115 is very difficult to debur, particularly around the entry port 113 of the outlet 112. This is because the cavity 115 and port 113 are located inside the valve body 102. Inevitably, therefore, small, sharp protrusions are left on the wall surface of the cavity 115. These protrusions tend to cut or slice the o-ring 128 as the plug 120 is rotated from the open to the closed position. Specifically, burs around the entry port 113 of the outlet 112 tend to slice the o-ring 128 as it slides past to reach the closed position. Once the o-ring 128 has been cut, it can no longer provide an adequate sealing function and gas will leak into the outlet 112 even when the valve 100A is closed.
In addition, the o-ring 128 of the prior art valve 100A is relatively large and pliable, e.g., a 007-70.degree. Urethane (U) or Ethylene Propylene (EP) o-ring. With this o-ring 128, when CO.sub.2 is used as the compressed gas, the o-ring 128 has a tendency to absorb the CO.sub.2 and expand as a result. Also, because the o-ring 128 is fairly large in proportion to the diameter of the plug 120, it tends to come out of its groove 129. Furthermore, pressure from the gas source tends to force the o-ring 128 into contact with the valve body 102. The expansion forces and gas pressure increase the contact between the o-ring 128 and the body 102, thereby increasing the likelihood that surface irregularities along the cavity walls (and particularly around the entry port 113 of the outlet 112) will destroy the o-ring 128. When the o-ring 128 is destroyed, the compressed gas begins to leak from the on/off valve 100A, shortening the life of the gas source. Because of this, the prior art on/off valve 100A is unreliable.